The present invention relates to a system for transmitting the power of an engine to four wheels of a four-wheel drive vehicle.
In a conventional four-wheel drive vehicle having a central differential, which is called a full time four-wheel drive vehicle, the central differential operates to uniformly distribute the torque of an engine to the front wheels and to the rear wheels.
It is known that the distribution ratio of torque influences the driveability, steerability, stability, starting characteristic and other factors of operation. Namely, when the distribution to the front wheels is increased, a stable cornering characteristic at high vehicle speed is established, and when the distribution to the rear wheels is increased, steerability at low vehicle speed is improved. In the conventional four-wheel drive vehicle, the distribution ratio of the torque for the front wheels to the rear wheels can not be changed.